TeleGeography: Ethernet VPLS, EoDWDM interest grows, while IP/VPN expansion dips
HISTORICAL SPACE FREQUENCIES. The first satellite to orbit the Earth was Sputnik 1, launched by the Soviets in October 1957. It carried two radio beacons on frequencies of 20.005 and 40.01 MHz. The Soviets continued to use frequencies around 20 MHz and even some around 15 MHz for many subsequent missions. This tends to be used for uplinks of the satellites that downlink in the 137 - 138 MHz band. 2  149.95 - 150.05 MHz. 3  This is used by satellites providing positioning, time and frequency services, by ionospheric research and other satellites.
A close-up photo of Earth (not to scale) The Earth rotates freely on its axis; this makes it a frequency standard. The nominal frequency is approximately 11.5 ÂµHz, or more exactly, 11.5740740e-6 Hz (a period of 86400 s). Unlike a 10811 which delivers a 10 MHz RF output the 11.5 ÂµHz frequency output of Earth is typically detected optically: either shine light onto earth or detect light from earth.